He had previously said he was not gifted the bottle of 1959 Penfolds Grange Hermitage in 2011 by Liberal Party donor Nick Di Girolamo, but documents from a courier company showed that it was delivered to his home.

Australia's Independent Commission Against Corruption, which is investigating the finances of Australian Water, heard that Mr Di Girolamo, its former chief executive, sent the wine to congratulate Mr O'Farrell for being elected to his post.

Tony Abbott, Australia's Prime Minister, said: "Barry is a man of honour. He is a man of integrity. He is a very decent man and I think he has been a very capable Premier over the last three years. I think he will be missed."

He also expressed confidence that Mr O'Farrell inadvertently misled the ICAC.

"This is the thing, if you're in public life, you meet lots of people, from time to time people give you things," Mr Abbott said.

"They might give you ties or pens or a bottle of wine, and sure, a bottle of Grange is pretty special, no doubt about that. Given that premiers and other senior politicians have very crowded busy lives, I don't think it is reasonable to expect everything from some years ago to be front of mind."

Mr O'Farrell had been due to make a speech at the Sydney Opera House reception. It is unclear whether his deputy will now deliver it instead.